A serial peripheral interface bus (SPI) is a synchronous serial data link standard that is in full duplex mode between a SPI master device and one of a possible many SPI peripheral devices. SPI devices typically have four transmission lines between the master and peripheral devices. Flexible protocol and simple hardware interfacing of SPI are some of its many advantages. SPI is often used in sensors such as temperature, pressure, analog to digital converters, and touch screens. SPI may also be used in control devices, camera lenses, communications such as Ethernet and USB, flash memory, real-time clocks, and LCD displays to name a few.